Adventure with another genuine hawk feather equipped until it disappears. You will immediately fight this opponent (note that you will have no offhand item equipped and your shirt will be the feathered cloak).

End of Fight

If you lost:

Moments later, everything seems to return to normal. The hawk and storm both fade as though neither were ever there.

If you won:

Moments after the hawk falls from the sky, the storm calms and your world returns to what passes for normal.